There is a forest of maker content, education etc out there. This is just a small, but expandable list of cool things some of us have seen on the internet.
YouTube
Let's start with the best and biggest: YouTube. You can practically find anything in here, so it is quite hard to filter it out. But we tried our best:
Hardware
pierogi engineering - One of the best and funniest. No one loves gyroscopes more than him.
Works By Design - Very high quality maker videos, big recommendation.
Henry Segerman - He is a (self prescribed) mathematical maker.
Matthew Lim - Quite soothing and relaxing videos about small maker projects.
Henry Kidman - High Energy + Cinematic maker videos.
DIYPerks - Building cool stuff.
ExcessiveOverkill - He makes "cool stuff". F.e. a fire lightsaber or working on an industrial robot arm.
HTXStudio - Entertaining, high quality maker content.
Engineezy - Visually pleasing (marble machines) and robots.
MadeByDennis - Specific crazy and cool projects.
soiboi soft - He is working on a very cool vacuum display. Big reccomendation.
Salim Benbouziyane - Very much a maker channel, also explains his projects and uploads the project files.
Educational
KnowArt - Educative channel about many mechanical concepts and how things work in general. Gives off "Sendung mit der Maus" vibes :).
Inside Everything - I mean the name says it all. He is going literally inside everything.
Technology Connections - Explains how Technology (f.e. Appliances) work
Posy - Cinematic, beautiful and calm videos about tech. Definitely a recommendation.
styropyro - He is rather destroying than creating, but very interesting.
MadeWithLayers - The guy for anything 3D printing
The Stock Pot - Does smart home content.
media.ccc.de - The ccc YouTube channel, where a subset of the talks are hardware related and quite interesting.
Stuff Made Here - Interesting contraptions and sciency topics
Electronics/Computers
Jeff Geerling - Mostly talking about Hardware and networking.
Christian Lempa - Services for self hosting and server stuff.
Axiometa - Technical, high quality maker content. Mainly LED Stuff.
bitluni - Lots of LED matrix stuff and he built a DIY RISC-V GPU.
GreatScott - Scott tells you all about microcontrollers and embedded projects.
This Does Not Compute - Has a lot of interesting vintage hardware projects
Hacking
f4mi - Less hardware, more hacky.
Benn Jordan - also rather hacky. If you want to know more about the american surveillance state, this is the channel.
Keyboards
Cheese Turbulence - He is building Keyboards, mostly.
Flurples - Flurples Law: If it can be a Keyboard, it will be a Keyboard.
Ben Vallack - Crazy guy building Keyboards and endlessly optimizing his work setup
3D Modelling
Deltahedra3D - CAD using FreeCAD. Good for beginners.
Ducky3D - Motion graphics and cinematic animations in Blender
Polyfjord - Modelling, 3D tracking, photogrammetry, basic CGI effects, fluid/smoke simmulation in Blender
Websites
3D Printing
Yeggi - A 3D model aggregator for community 3D Models. No need to go to every website below (even though website specific searches work better sometimes)
Maker World (Bambu Lab) - Bambu Labs own 3D model community.
Printables - Prusas own 3D model community.
Thingiverse - Another 3D model community.
Manufacturing
JLCPCB - Here you can order PCBs, 3D Prints, CNC parts, metal sheet parts etc. (PCBWay)
Reichelt - Electronics store.
Mouser Electronics - Electric components, mostly for PCBs